I use my Macbook hooked up to a TV via HDMI for most of my work, and want to use Airplay mirroring from my Mac to extend my desktop and play online videos full screen on my Apple TV while also being able to do work on my computer that won't end up on the screen. It seems to me that using airplay mirroring with the "desktop extension" option is the best way to do this. However, whenever I turn it on, all of my apps end up on the TV screen and my desktop ends up completely blank. Is there a way to choose which desktop is the one that goes on to the TV?
When you switch from Mirroring to Extended Desktop
To move open windows, or Applications, to the Apple TV display simply click and drag the window by the Title Bar to the left hand side of your display (keep dragging over the screen edge). As you do this the window will appear in a transparent view on the Apple TV display. Once the entire window is on the new display, it will become active and can be interacted with in your second workspace........
You can also use Mission control and just drag the allocations between the displays.
And the cmd left arrow